--- a/graal/com.oracle.graal.loop/src/com/oracle/graal/loop/LoopFragment.java	Tue Sep 03 18:19:30 2013 +0200
+++ b/graal/com.oracle.graal.loop/src/com/oracle/graal/loop/LoopFragment.java	Wed Sep 04 09:39:51 2013 +0200
@@ -145,11 +145,11 @@
         }
     }
 
-    protected static NodeBitMap computeNodes(Graph graph, Collection<AbstractBeginNode> blocks) {
+    protected static NodeBitMap computeNodes(Graph graph, Iterable<AbstractBeginNode> blocks) {
         return computeNodes(graph, blocks, Collections.<AbstractBeginNode> emptyList());
     }
 
-    protected static NodeBitMap computeNodes(Graph graph, Collection<AbstractBeginNode> blocks, Collection<AbstractBeginNode> earlyExits) {
+    protected static NodeBitMap computeNodes(Graph graph, Iterable<AbstractBeginNode> blocks, Iterable<AbstractBeginNode> earlyExits) {
         final NodeBitMap nodes = graph.createNodeBitMap(true);
         for (AbstractBeginNode b : blocks) {
             for (Node n : b.getBlockNodes()) {
@@ -229,12 +229,28 @@
         return false;
     }
 
-    public static Collection<AbstractBeginNode> toHirBlocks(Collection<Block> blocks) {
-        List<AbstractBeginNode> hir = new ArrayList<>(blocks.size());
-        for (Block b : blocks) {
-            hir.add(b.getBeginNode());
-        }
-        return hir;
+    public static NodeIterable<AbstractBeginNode> toHirBlocks(final Iterable<Block> blocks) {
+        return new AbstractNodeIterable<AbstractBeginNode>() {
+
+            public Iterator<AbstractBeginNode> iterator() {
+                final Iterator<Block> it = blocks.iterator();
+                return new Iterator<AbstractBeginNode>() {
+
+                    public void remove() {
+                        throw new UnsupportedOperationException();
+                    }
+
+                    public AbstractBeginNode next() {
+                        return it.next().getBeginNode();
+                    }
+
+                    public boolean hasNext() {
+                        return it.hasNext();
+                    }
+                };
+            }
+
+        };
     }
 
     /**